Motoshi Ichinose

Hereditary factors in the craniofacial morphology of Angle's Class II and Class III malocclusions

We attempted to assess the role of heredity in the development of Angles Class II and Class III malocclusions by comparing craniofacial morphologic differences between parents with Class II offspring and those with Class III offspring and by analyzing the parent-offspring correlations within each Class II and Class III malocclusion group. Lateral and frontal roentgenographic cephalograms were obtained for ninety-six patients with Class II malocclusion, 104 patients with Class III malocclusion, and their respective parents. Mean cephalometric profile diagrams were superimposed between the two groups of parents as well as between their offspring. Within the two groups, the parent-offspring correlation coefficients were computed for nineteen variables connecting cephalometric landmarks. The differences in the craniofacial complex were evident in the two groups of parents as well as in their offspring. High correlation coefficient values were seen between parents and their offspring in the Class II and Class III groups. Thus, there appears to be a strong familial tendency in the development of Class II and Class III malocclusions. We conclude that the hereditary pattern must be taken into consideration in the diagnosis and treatment of patients with these classes of malocclusion.

Characteristics of craniofacial structures of parents of children with cleft lip and/or palate

We looked for possible differences in craniofacial morphology between parents of children with celft lip (CL) and/or cleft palate (CP) and normal controls. Fifty measurements were obtained from lateral and frontal roentgenographic cephalograms of these subjects. The means of all measurements were tested for significant statistical differences, and a discriminant analysis was carried out to distinguish the craniofacial structures in the experimental subjects from those in the controls. Facial shape of parents of children with CL and/or CP differed from that of control subjects. Shorter height and greater width in the upper face were the main characteristics of facial shape of parents of CL and/or CP children. Craniofacial morphology was considered to be related to susceptibility to these facial deformities.

Relationship between tongue volume and lower dental arch sizes

The interrelation between the tongue volume and the lower dental arch sizes (arch width and area) was studied by the original methods that we developed. A plane perpendicular to the occlusal plane and 40 mm posterior to the lower incisal point was taken as the posterior border of the tongue and the arch. The tongue volume and the lower dental arch sizes were measured anterior to this border with plaster models. The correlations between the parameters obtained from 74 Japanese adults (37 men and 37 women) with normal occlusion were statistically analyzed. The results showed that (1) both the mean tongue volume and the mean lower dental arch sizes were significantly larger in men than in women; (2) the tongue volume and the lower dental arch sizes were significantly correlated; and (3) these correlations tended to be higher at the more posterior part of the dental arch.

Genetic and environmental factors in the development of so-called pseudo- and true mesioclusions

Abstract Separation of genetic and environmental factors related to the development of so-called pseudo- and true mesioclusions was attempted and the classification, which is in common use in clinical orthodontics, reconsidered. A differential diagnosis of these two types of mesioclusions was made depending on whether or not the mandible slid forward into displacement by incisal guidance. By means of lateral roentgenographic cephalograms obtained from 66 pseudo- and 48 true mesioclusion patients and 52 control subjects, and their respective parents, the craniofacial morphogenetic characteristics of each mesioclusion were determined. A familial tendency to prognathic skeletal profile was noted in cases of both pseudo- and true mesioclusions. Nearly all of the significant morphogenetic differences between the two groups of patients with mesioclusion were related to environmental factors. The terms “pseudo” and “true” are probably misleading expressions for these mesioclusions.

Molecular Basis of β-Thalassemia in Japan: Heterogeneity and Origins of Mutations

Characterization of β-thalassemia mutations was attempted for 13 unrelated Japanese patients heterozygous for β-thalassemia. We have systematically analyzed β-thalassemia genes using polymerase-chain-

Role of parental variables in predicting facial growth after treatment of anterior crossbite

A pilot study was done to determine whether parental cephalometric variables could be used to better predict craniofacial dimensions in their offspring. The sample consisted of lateral roentgenographic cephalograms from 41 children who had been treated with functional appliances for anterior crossbites and from their respective parents. The actual mandibular prognathic growth change of each child after treatment was determined from two profile radiographs over a 3-year period. Morphologic features after treatment and those of the respective parents were compared with the observed yearly growth change, and the predictive values were calculated by means of uni- or multivariate analysis. The best fit predictive formula was obtained by the total observation of variables from both children and their parents by means of multiple regression analysis in which the correlation coefficient exceeded 0.9 despite a value of less than 0.5 when the variables were analyzed separately by simple regression analysis. Thus, to predict the craniofacial growth for a given type of child, the dimensions of the child in addition to those of his or her parents (hereditary) seem to be a valid approach.

PI*Siiyama, a deficiency gene of alpha1-antitrypsin: Evidence for the occurrence in western Japan

SummaryAn alpha1-antitrypsin deficiency associated with pulmonary emphysema was investigated in a 32-year-old Japanese male. Polymerase chain reaction (PCR)-amplified fragments and dot blot hybridization with allele-specific oligonucleotide probes revealed that the patient was homozygous for a C to T transition at codon 53, resulting in the substitution of Phe53 for Ser53 (PI*Siiyama). Crossedimmunoelectrophoresis after iso-electric focusing and agarose gel electrophoresis showed atypical banding patterns. PI* Siiyama is a rare deficiency gene, but it can occur sporadically all over the Japan.